Coil winding mandrel



Jan. 2, 1934. J. G. MEYERS con WINDING MANDREL Filed Dec. 6, 1929 2Sheets-Sheet l Jam-2, 1934- J MEYERS 1,942,113

COIL WINDING MANDREL Filed Dec. 6, 1929 2 Sheets-Sheet 2 Patented Jan.2, 1934;

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COIL WINDING DIANDREL John G. Meyers, Rome, N. Y., assignor to GeneralCable Corporation, New York, N. Y., a corporation of New JerseyApplication December 6,1929. Serial No. 412,050

6 Claims.

This invention relates generally toapparatus for winding coils of wire,and more particularly to an expansible and collapsible mandrel formaking layer wound coils.

It is an object of this invention to provide an improved mandrel forwinding layer wound coils of the type in which the turns of the firstlayer are positioned according to a predetermined plan, and the turns ofsucceeding layers lie, except for short distances at points ofcross-over, in the grooves between the turns of the immediatelypreceding layer. Other objects and advantages of the invention willappear hereinafter.

An illustrative embodiment of the invention selected merely fordescriptive purposes is shown in the accompanying drawings, in which:

Fig. 1 is an end view of a mandrel;

Fig. 2 is a side view of the mandrel, partly broken away to show asection substantially on line 22 of Fig. 1;

Fig. 3 is a view similar to Fig. 2, but with the mandrel rotated 96,about its longitudinal axis, the view being a section substantially online 33 of Fig. 4; and

Figs. 4 to 6 are sections on the correspondingly numbered lines on Fig.3.

In winding multiplelayer coils in which the layers are not spaced fromeach other, as by means of sheets of insulating material, it will beapparent that for a coil having a fixed number of turns of a given sizeand kind of wire the cross-sectional area of the coil wall transverse tothe direction of the coil turns may be reduced to a minimum only whenthe space between adjacent coil turns is reduced to a minimum.

In winding coils of round wire, the space be tween coil turns may bereduced to a minimum only when each of the coil is wound accurately inaccordance with a predetermined plan utilizing the available space tothe best advantage. Preferably, the turns of the first coil layer lie,except for short distances at the points of cross-over between turns, inplanes perpendicular to the longitudinal axis of the coil, and arespaced from wire center to wire center a distance slightly greater thanthe maximum wire diameter. The turns of the succeeding layers lie,except for short distances at the points of cross-over in the groovesbetween the turns of the preceding layer. Such a coil will have smalleroverall dimensions than a coil of the same number of turns and kind ofwire wound in some other manner, and consequently will require less wirefor a given number of turns.

Referring to the drawings, andparticularly to Figs. 2 and 3, a spindle11 is provided at one end with means such as the screwthreaded portion12, whereby the spindle may be detachably secured by its end to arotatable shaft, (not shown) conveniently that of a coil windingmachine, or an electric motor. Adjacent the screwthreaded portion 12 thespindle 11 is enlarged to form a. collar 13, and abutting the collar 13is a head flange 16 which may be slipped into place over thescrewthreaded end 14 of the spindle. The head flange has on its facetoward the end 14 of the spindle a frusto-conical shaped collar 18, thepurpose of which will become apparent hereinafter. The head flange 16also has a plurality of radially extending slots 19, for example fourslots spaced equally about the flange. These slots 19 extend from thecircumferential edge of the head flange inwardly substantially to theouter surface of the core upon which the coil is to be wound, and theirfunction will appear hereinafter. Thelhead flange preferably is securedagainst longitudinal movement along, and turning movement about thespindle in any suitable manner, as by means of a pin 1'7.

Referring particularly to Fig. 2, the head flange 16 has a plurality ofcircumferentially spaced guide pins 20 projecting from its face awayfrom the collar 13, each pin lying substantially parallel to theinclined surface of the collar 18. These guide pins, of which in theembodiment disclosed there are two diametrically spaced from each other,may be secured in the flange in any suitable manner, conveniently byfrictional engagement, and preferably extend through and project beyondthe other face of the head flange, whereby they may be adjustedlongitudinally. Each pin 20 slidably engages an opening 21 in one end ofa corresponding core member 22, the core members collectively forming asupport or core upon which a coil may be wound.

In the particular embodiment disclosed there are two arcuate shaped coremembers 22 forming a substantially cylindrical core for winding roundcoils. When the ends of the core members are in contact with the headflange 16, adjacent longitudinal edges of the core members are separatedby relatively narrow gaps, thereby permitting radial movement of thecore members inwardly to collapse the mandrel as hereinafter described.The ends of the core members adjacent the head flange 16 have theirinner sur-- faces tapered to bear on the frusto-conical shaped collar18. The core members are movable longitudinally, and because of theoperative connection with the inclined pins 20 have concurrently aradial movement. Conveniently the pins 20 are so adjusted that when thecore members 22 are moved longitudinally and inwardly, as the mandrel isbeing collapsed, until they contact with the spindle 11, the pins 20still. engage the openings 21 to retain the parts in assembled relation.

The ends of the core members 22 distant from the head flange 16conveniently are provided with means normally tending to draw the coremembers together, for example, circumferentially aligned recesses 23retaining an annular spring 24, for example a spiral tension spring withits ends connected together. The inner surfaces of the ends of the coremembers are tapered similarly to the ends adjacent the head flange 16for slidably engaging a frusto-conical shaped collar 25 on the innerface of a tail flange 26. The tail flange 26 may be slipped on to thespindle 11 over the screw-threaded portion 14; and

has a plurality of radially extending slots; 32, similar to, andanularly aligned. with the slots- 19. in the head flange 16,. Relativerotation be: tween the tail flange and the spindle 11 may be preventedby meanssuch as apin 30;,secured in the spindle ll for engaginganarrow.slot or keyway 15 in the, inner edge of the tail flange,

Suitable means. are provided for forcing the tail flange 26, againsttheends of the core members, and the core members against, the head flangeto expand the mandrel, and for main taining the mandrelin expandedcondition, during the. winding operation. Merely by wayof example in theembodiment disclosed, a nut 27 engages the screwthreaded end i l. of thespindle 1'1, and may be screwed into place to force the tailflange26against the ends'of thev core members, at the same time movingthe-core'members longitudinally. toward the flange 16, andradiallyoutward due to the engagement of the collars 18- and 25with the taperedends of the core men bers. erably is multiple. and coarse. As the nut2'7'is unscrewed, the. core members are permitted to move.longitudinally and radially. inward under the. influence of: the spring24.

Conveniently, the nut 27 isrotatably secured on the'outer face of thetail flange 26, as by means ofa. split plate 33 engaging acircumferential groove 34in thehub of the nut, the plate 33 beingsecured on the. outer face ofthe flange by screws. Thus it will be seenthatthe core members 22'form anexpansible and collapsible coil windingsupport or core from which coils readily may be removed by removing thenut27' and the tail flange 26.

In order to insure contact of the core members 22 with thefrusto-conical hub 25 on the tail flange when the mandrel is expanded,it may be desirable to-providethe tail flange with means such as thepositioning pins 28'for engaging the recesses in the ends of the coremembers 22'when the tail flange is forced against the ends of the coremembers to force the ends of the core members against the hub 25.

The core members 22 are provided on their outer surfaces with ridges forpositively positioning and holding the turns of the first coil layer inaccordance with a predetermined plan.

Preferably the wire positioning ridges are formed by grooving the outersurfaces of the core mem bers in a plurality of substantiallyequally-spaced parallel grooves lying in planes perpendicular to thelongitudinal axis of the mandrel, the spac- For speed inoperation thethread pref ing of said grooves from root center to root center beingsubstantially equal to, and preferably slightly greater than the maximumoverall wire diameter, the grooves of the various core members beingcircumferentially aligned when the mandrel is expanded preparatory towinding a coil. In practice there are slight variations in wirediameter, even in short lengths of wire, and for this reason it isdesirable to make the spacing of the grooves slightly greater than themaximum wire diameter, for example 1 to 2 greater.

The winding core has one or more narrow recessed Zones. from which thewire-positioning ridges have been removed extending longitudinallytherealong. In the embodiment disclosed, eachof thetwo members 22 hassuch a narrow recessed Zone 29 extending along each of its longitudinaledges. These narrow recessed zones prevent; the wire-positioning ridgesfrom interfering with the turns of the inner layer when a coil is movedofi'jfrom the-collapsed-mandrel.

The; operation of winding acoil, on the. mandrel nowwill be described;The mandrel is secured by means of the screwthreadedportion 12. to arotatable, shaft, conveniently the-winding shaft of: acoil winding;machine, The mandrel is assembled, the nut27beingscrewed uptight onthe-end: 14 of the spindle. 1 l to-expand the wire receiving core, toits maximum dimensionsandto move the head; and. tail flangesagainsttheends of; the core members 22.,

The endof the wire is secured, ,forexample-t0 aclip'3l on the outer faceofithe-tail flange, conveniently integral with the split plate 33,whence it passes through oneof theslots 32 into-theflrst circumferentialgroove, of the wire receiving core. The mandrel is then rotated,vsuitable tension being maintained on the wire,- and upon the substantialcompletion of one full turn the-wire by reason of the-tension exerted onit and its riding up on the first part of the-turn,,ismovedlongitudinally alongthe mandrel-a distance substantiallyequal tothediameter of the wire, and is drawn down intothe next. circumferentialgroove. rotation of the mandrel.

If the distance between the mandrel and the wire supply or wire guide isnot too short relative to the length of the coil to be wound, the wirewill move automatically from one groove to the next groove when the wireengages the first part of the turn, and no additional means will berequired for causing the wire to move longitudinally along the mandrel.In other cases it may be found desirable to provide a suitabletraversing wire guide moving back and forth parallel to the rotatingmandrel to insure the d sired laying on of the wire in the grooves.

This action is repeated upon further When the last completecircumferential groove on the mandrel core has been filled, the wirewill rideup on the top of the first coil layer, and, under tension, willfall into a groove between either the last turn of the first layer andthe head flange, or in the groove between the last two turns of thefirst layer. The course taken here by the wire is dependent upon whetherthe last groove on the wire receiving core brings the last turn of thefirst layer one half a wire diameter distant from the head'flange, orflush against the head flange. If the last groove of the wire-receivingmandrel core is a full groove, the even numbered layers of the coil willeach have one less turn than the odd numbered layers, while if the lastgroove of the core is a half groove each coil layer will have the samenumber of turns.

In the embodiment shown the last groove is a half groove. Upon furtherrotation of the mandrel the second and following co-il layers are woundas was the first, the turns of the preceding layers serving as the wirepositioning ridges.

When the desired number of turns have been wound on the mandrel,rotation is stopped, the wire is severed, and the coil end is secured inany suitable manner to prevent unwinding of the coil. U-shaped clampingmembers then are positioned on the coil, the legs of the clampingmembers engaging the ends of the coil through the slots 19 and 32, andthe nut 27 is unscrewed.

The inner end of the coil wire may be loosened from the clip 31 beforethe nut 2'7 is unscrewed, but preferably the nut is at least partiallyunscrewed before the wire is detached from the clip 31 in order that asthe nut is unscrewed, the coil and the core members 22 will be moved1ongitudinally of the mandrel with the tail flange 26 to aid incollapsing the mandrel, the core members 22 also moving radially inwardunder the influence of the spring 24 and the guide pins 20 as they aremoved longitudinally. When the nut is loosened, the turns of the coilexpand slightly, this expansion being limited by the clamping members.The coil with its attached clamping members may then be slipped oif ofthe coilforming core, either with or subsequent to the removal of thetail flange and nut 27, the core members 22 moving toward each other tocollapse the mandrel and withdraw the wire-positioning ridges fromengagement with the inner layer of the coil. The coil then may be tiedand finished in the usual manner.

It will be seen that this invention provides a mandrel which is simplein construction and operation, and which is adapted to wind accuratelyand at high speed layer wound coils having minimum overall dimensions.

It will be understood that the invention may be variously modified andembodied within the scope of the claims.

I claim:

1. An expansible and collapsible coil winding mandrel comprising, incombination, two arouate-shaped sectional members forming asubstantially cylindrical mandrel core, each of said sectional membershaving on its outer surface a plurality of wire-positioning ridges, theridges of the two members being circumferentially aligned, and lying inequally-spaced parallel planes perpendicular to the longitudinal axis ofthe core, a narrow zone from which the ridges have been removedextending longitudinally along each edge of each of the sectionalmembers to permit removal of a completed coil from the mandrel when incollapsed condition, end flanges for said core, and means on said endflanges for forcing the sectional members apart to expand the mandrelcore as the end flanges are pressed against the ends of the core.

2. An expansible and collapsible coil winding mandrel comprising, incombination, a longitudinally split cylindrical mandrel core, the outercylindrical surface of said core being grooved with circumferentiallyaligned wire-receiving grooves lying in planes perpendicular to the axisof the core, a narrow zone from which the ridges between the grooveshave been removed extending along each longitudinal edge of each sectionof the core to expedite removal of a coil from the mandrelwhen incollapsed condition, end flanges for said core, and means for moving thetwo halves of the core apart to expand the mandrel.

3. An expansible and collapsible coil winding mandrel comprising, incombination, a plurality of sectional members forming a mandrel core, anend flange for said core, a plurality of guide pins extending from theinner face of said end flange and slidably engaging openings in the endsof said sectional members, the arrangement of the guide pins being suchthat movement of the sectional members toward and away from the endflange is accompanied by radial movement of the sectional membersoutwardly apart and inwardly together, means normally tending to movesaid sectional members radially inward to collapse the mandrel, a secondend flange, means on the inner face of said second-mentioned end flangefor forcing the sectional members radially outward when the end flangeis pressed against the end of the core, and means for pressing saidsecond-mentioned end flange against the end of the core to expand themandrel.

4. An expansible and collapsible coil winding mandrel comprising, incombination, a plurality of sectional members forming a mandrel core, anend flange for said core, a plurality of guide pins extending from theinner face of said end flange and slidably engaging openings in the endsof said sectional members, the arrangement of the guide pins being suchthat movement of the sectional members toward and away from the endflange is accompanied by radial movement of the sectional membersoutwardly from each other and inwardly toward each other, a second endflange, and means for pressing said second-mentioned end flange againstthe end of the core to expand the mandrel.

5. An expansible and collapsible coil winding mandrel comprising, incombination, a plurality of sectional members forming a mandrel core,end flanges for said core, a plurality of guide pins extending from theinner face of one of said end flanges and slidably engaging openings inthe ends of the being inclined inwardly toward the longitudinal axis ofthe core, and means for pressing the flanges against the ends of thecore to expand the mandrel.

6. An expansible and collapsible coil winding mandrel comprising, incombination, a plurality of arcuate-shaped sectional members forming amandrel core having on an end face acircumferentially extending groove,an annular spring lying in the said groove and normally tending to drawthe members together to collapse the mandrel, wire positioning ridges onthe outer surfaces of said sectional members, end flanges for said core,and means on said end flanges for forcing the core members apart toexpand the mandrel.

JOHN G. MEYERS.

core members, said pins

